Delay interferometer

Abstract

In a delay interferometer in which a Michelson delay interferometer unit is mounted in a package, the delay interferometer includes: a Michelson delay interferometer unit in which A-channel interference output light obtained by optically processing input light that is formed by splitting input light received through an input port, into A and B channels through a splitting portion is output from an A-channel first output port and an A-channel second output port disposed, and B-channel interference output light is output from a B-channel first output port and a B-channel second output port; and a first optical path length compensating member which is interposed between the A-channel interference output light or the B-channel interference output light, and the A-channel first output port or the B-channel first output port.

Description

[0001]This application claims priority to Japanese Patent Application No. 2008-152243, filed Jun. 10, 2008, in the Japanese Patent Office. The Japanese Patent Application No. 2008-152243 is incorporated by reference in its entirety.TECHNICAL FIELD[0002]The present disclosure relates to a delay interferometer using a spatial optical system, which is used for demodulating a differential phase shift keying signal in optical fiber communication, particularly in optical fiber communication using a dense wavelength division multiplexing (DWDM) system.RELATED ART[0003]In optical fiber communication using a DWDM system, an optical signal which is modulated by the differential phase shift keying method (DPSK) or the differential quadrature phase shift keying method (DQPSK) is mainly transmitted, and a received optical signal is demodulated by a demodulator including a delay interferometer.[0004]As a delay interferometer using a spatial optical system, a Michelson delay interferometer is well...

AI Technical Summary

Benefits of technology

[0008]Exemplary embodiments of the present invention provide a delay interferometer in which the difference of optical path lengths to output ports in the delay interferometer can be easily corrected.

Problems solved by technology

When it is assumed that the optical detector 122 is an optical fiber, axis and angle deviations in the optical axis are produced in the mirror 116 or 117 by position and angle errors of the mirror surface, thereby producing a problem in that the coupling to the optical fiber is hardly performed.

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